.header-logo {
    position: relative;
    margin  : 0 0 0 100px;
}

/* 设置a标签的样式 */

.logo {
    display         : block;
    width           : 55px;
    height          : 55px;
    overflow        : hidden;
    background-color: #ff6700;
    text-align      : left;
    text-indent     : -9999em;

    div {
        // display: flex;
        // width  : 110px;

        div {
            position: absolute;
            top     : 0;
            left    : 0;
        }

        .a1 {

            width     : 55px;
            height    : 55px;
            /* 设置过渡 */
            transition: all .3s;
            /* 背景图片 */
            background: url(../images/mi-logo.png) no-repeat center center;
            /* 透明度 */
            opacity   : 1;
            transform : translateX(0);
        }

        .a2 {

            width     : 55px;
            height    : 55px;
            transition: all .3s;
            background: url(../images/mi-home.png) no-repeat center center;
            transform : translateX(0);
            opacity   : 0;
        }

    }

    &:hover {
        .a1 {
            opacity  : 0;
            transform: translateX(55px);
        }

        .a2 {
            opacity  : 1;
            transform: translateX(-55px);
        }
    }
}